It has been announced earlier this week that the Psyllid is to be released into Southern England, later this year. The psyllids are intended to act as a biological control of Japanese knotweed and the hybrid Fallopia x Bohemica. We are mainly supportive of this initiative as Japanese knotweed continues to spread unchecked throughout the British Isles. There is simply no funding or compulsion on landowners to treat their Japanese knotweed problems, so if we do not take more action, we will continue to see knotweed gaining on us. This is not without a cost both financially and for our environment.
However, the psyllid will not eradicate knotweed. It may (at best) reduce the plants vigour and limit the future spread. This will be helpful to us in our continuing efforts to control/eradicate Japanese knotweed, but is not a solution in itself.
Construction sites will still need to have our full range of services for decades to come, as the psyllid can only act on above ground growth. As now, if a building is constructed on Japanese knotweed without correct and appropriate remediation or barriers, the knotweed will quickly penetrate the building and cause major damage.
The main benefits for this release will be the reduction of the currently uncontrolled spreading of Japanese knotweed in both urban and country areas, where no development is planned. In these areas, we can expect (probably by 2020!) to see a level of control being achieved, which may make a combined herbicide/psyllid programme more effective than the available current herbicide programmes. The key word here is ‘may’, evidence of enhanced herbicide activity in psyllid damaged knotweed does not reliably exist.
The decision to release has been made; it may alter some of our management practices in the future, but for now and for the foreseeable future, people and companies will need to get appropriate professional advice and suitable solutions for their knotweed problems.
